Most mixer taps using cartridges with ceramic disks currently fitted to sinks or washbasins cannot effectively stabilize the temperature of the outflowing fluid, referred to herein as the “mixed” fluid, in the event of significant and/or sharp variations in the pressure and/or temperature of either or both of the incoming fluids, referred to herein as the “hot fluid” and the “cold fluid”.
Cartridges of this type have therefore been proposed in the past that are equipped with a thermostatic element to regulate the temperature of the outflowing fluid.
The document WO 96/26475 in particular discloses a single-lever thermostatic cartridge for use in “mixer” taps in which the flowrate and the temperature of the outflowing fluid are adjusted by operating a single control, whence the term “single-lever”. This type of cartridge adjusts the flowrate and the temperature by means of two superposed ceramic disks, the lower disk including respective upward passages for the cold and hot fluids and respective downward passages for the cold and hot fluids. The temperature of the outflowing mixed fluid is thermostatically regulated by a temperature regulation slide valve downstream of and below the lower disk and fastened to a thermostatic regulation element familiar to the person skilled in the art.
However, the diameter available for the regulator slide valve and the fluid flow sections are limited by the geometry of the cartridge, in particular by the relative disposition of the upward and downward passages for the cold and hot fluids. Because the flowrates of the fluids to be mixed are low, a weak flow results around the thermostatic element, whence poor temperature regulation, which is incompatible with the standards in force for thermostatic taps, and a low output flowrate, which limits the range of potential applications.
This drawback is all the more marked when the cartridge dimensions suit mixer taps with a standardized outside diameter of the order of 46 mm, with the aim of enabling replacement of a non-regulated cartridge with a thermostatically regulated cartridge.
An object of the invention is to remedy these drawbacks by proposing a single-lever thermostatic cartridge which regulates temperature more effectively than prior art cartridges over a wide range of flowrates.